The present invention relates to teat cup assemblies for vacuum operated milking machines, and more particularly to an inflation for use in a teat cup assembly having a predetermined collapsed massage profile.
Conventional automatic milking machines utilize teat cup assemblies for milking cows. A typical teat cup assembly includes a hollow, rigid outer shell or cup adapted to be attached to a pulsating vacuum line, and an elongated, flexible, resilient, tubular inflation which fits inside the shell and is coupled with a constant vacuum source. Typically, the inflation includes an upper mouth, a barrel defining a teat receiving region, and a milk tube section which extends downwardly out of the shell or cup and is attached to a milk claw for collecting milk. The upper mouth as well as the milk tube section are both sealingly engaged with the upper and lower ends of the shell, respectively, to form an annular vacuum chamber surrounding the barrel between the shell and the inflation. As previously noted, since the shell is attached to a pulsating vacuum line, the pressure in this annular chamber is alternated between subatmospheric pressure and atmospheric pressure. The constant vacuum applied to the lower milking tube section of the inflation draws milk from the cow""s teat while at the same time the alternating pressure in the annular chamber periodically causes inward collapse of the barrel wall of the inflation or liner resulting in a massaging action on the teat. Also, the periodic collapse of the barrel intermittently relieves the teat from exposure to the constant vacuum applied to the interior of the inflation, and thus advantageously avoids complications such as inflammation of the teat as well as a tendency to induce mastitis.
Inflations are typically composed of elastomeric materials due to the resilient nature of such materials, i.e. their capability of recovering to their original size and shape after repeated deformation. Inflations are most often made from a natural or synthetic rubber composition, e.g. silicone rubbers have been proposed and used in certain circumstances. Each of these materials have their own unique advantages and disadvantages. For example, natural or synthetic rubber compositions are more resistant to tearing or ripping, but are subject to attack by oils, butterfats, teat treatment preparations and other chemicals used in the milking process. On the other hand, silicone rubbers are substantially less vulnerable to attack by such chemicals, and thus, have relatively long useful life. However, silicone rubber tends to tear and puncture more easily than rubber.
It is also known that due to manufacturing tolerances and as a result of different manufacturing techniques, inflations composed of the same material do not always have identical collapsed massage profiles. In other words, the dynamics of an inflation used in one teat cup assembly may be significantly different from what appears to be an identical inflation used in another teat cup assembly. Thus, it would be an advantage in the art to provide a teat cup assembly which utilizes an inflation having a predetermined and desired massage profile. Such an assembly would override any inherent manufacturing tolerances and/or defects from one inflation to the next.
A teat cup assembly for use with a milking machine for milking cows. The teat cup assembly comprises a shell including a hollow tubular body having an outer wall together with an inflation including a hollow tubular barrel disposed within the tubular body of the shell. The barrel defines a teat receiving region and has an outer wall spaced inwardly from the outer wall of the shell to define a vacuum chamber. The inflation is deformable between a relaxed profile and a collapsed massage profile around the teat of a cow. The teat cup assembly includes reinforcing means for predetermining a desired collapsed massage profile for the barrel of the inflation. The reinforcing means comprises at least one elongated, axially extending interconnection between the barrel and the shell. This interconnection may be either a mechanical interconnection or a chemical bond between the barrel and the shell. Preferably, the reinforcing means is a mechanical interconnection comprising at least one rib projecting either inwardly from the outer wall of the shell or outwardly from the outer wall of the barrel, together with at least one corresponding elongated, axially extending, mating rib-receiving groove formed in the other of either the outer wall of the shell or the outer wall of the barrel. Preferably, there are a plurality of circumferentially spaced ribs projecting from the barrel of the inflation, and there are a corresponding plurality of rib-receiving grooves formed in the inner surface of the outer wall of the shell. Most preferably, there are three equiangularly spaced apart ribs and three corresponding grooves, but depending upon the cows being milked, the number of ribs and grooves may be as few as one and as many as four.
In a preferred form of the teat cup assembly, the shell includes an upper end having an axially extending rim defining an annular recess and a lower end having a radially extending rim defining an opening of reduced diameter. The inflation includes a head portion dimensioned to fit within the annular recess, and a milking tube section extending through the opening in the lower end of the shell. An upper seal between the head portion of the inflation and the upper end of the tubular body of the shell is preferably formed by an expandable ring disposed within the head portion of the inflation which urges the head portion radially outwardly against the axially extending rim of the shell. A lower seal between the milking tube section of the inflation and the lower end of the tubular body of the shell is preferably formed by a radially extending, integral, annular, external flange projecting from the milking tube section which abuts against the radially extending rim of the shell.
The present invention thus provides a teat cup assembly wherein the inflation and shell have been modified to provide reinforcing means for predetermining a desired massage profile for the barrel of the inflation when collapsed. This massage profile is preferably triangular in shape, and thus overrides any inherent inconsistencies in manufacturing processes and/or materials of construction. Thus, the inflation will always collapse in a known or predetermined massage profile.